A ratio is defined as a comparison of two quantities by what method?

A ratio compares two quantities by division, which is why the answer is correct. When you express a ratio, you essentially divide one quantity by another to see how many times one value contains the other. This results in a relationship that can be represented as a fraction, which makes it easy to understand the relative sizes of the two quantities involved.

For example, if there are 2 apples and 3 oranges, the ratio of apples to oranges can be written as 2:3, which is derived from the division of the number of apples by the number of oranges (2 divided by 3). This division highlights the relationship and allows for easier comparisons between different sets of quantities.

The other methods listed may involve calculations with numbers but do not effectively express the comparative relationship between two distinct quantities in the same way division does. Addition sums the quantities but does not establish a direct comparison. Multiplication alters the magnitude but does not define the ratio itself. Subtraction also results in a difference without offering insight into how the two quantities relate to one another in a comparative sense.